Patent GB-1062250-A (GB)
Title: Improvements in or relating to apparatus for laying ocean cables and the like
IPC: E02F5/14
Filed: 1965-06-16
Abstract: 1,062,250. Laying pipes. R. HARMSTORF. June 16, 1965 [June 18, 1964], No. 25503/65. Heading F2P. [Also in Division H2] The Figure shows equipment for simultaneously cutting the sea bed and burying pipes or cable in it. A pair of pontoons 1 are arranged side by side and divided into cells which may be flooded to sink the arrangement or pumped dry by compressed air bottles located in one or more of the compartments and controlled electrically from the surface. Between the pontoons is supported a frame 11 which is hollow and is journalled to bearings carried by a subsidiary frame 10 mounted on the pontoons. This frame carries the plough at its lower end. Attached to the cradle are a pair of coupled beams journalled at one end to frame 10 and at the other end to the cradle. The beams, and with them the cradle, can be tilted by hydraulic cylinders 15 supplied with pressure from an electrically driven pump 18 mounted on a subsidiary frame 10 and controlled from the towing ship. This arrangement allows the cradle and plough to be rotated to the position shown dotted. The entire frame can be adjusted along the pontoons and clamped in a selected position so as to adjust the centre of gravity of the device. To prevent the nose of the device from burying in the bottom and causing the back to lift, rollers 24 are held out in front of the pontoons on a subsidiary frame 7 and the frame is adjusted longitudinally to alter the spacing of the rollers from the machine. On top of the cradle is mounted a vibrator 17 which vibrates the plough through the cradle so as to help it to enter the sea bottom. The cradle bearings are such as to stop the vibrations from being transmitted to the pontoons. An hydraulic pump is mounted in one of the pontoons and supplies water under pressure to a chamber in the bottom of the cradle and thence to the interior of the plough. Plough construction (Figs. 5, 6-11, 12 and 13, all not shown).-Three types of plough are described suitable respectively for soft medium and hard bottoms. That described with reference to Figs. 6-11 is open at the front and comprises two hollow side members 26 with forwardly facing inclined nozzles from which pressure water is forced and with an inclined channel between them which the cable enters near the top of the plough at the front and leaves at the bottom of the plough at the rear. The front of the channel is wider than the rear and there are holes in the side members so that stones and mud are forced out sideways by the movement of the plough. The upper nozzles 25 are inclined upwardly and the lower downwardly. Strengthening ribs are provided on the side members. The construction of Figs. 12 to 13 for the medium bottoms is closed at the front of the plough which is provided with a toothed leading edge 69 for cutting into the bottom under the impact of the vibrator. The interior of the plough is subdivided .into a number of water channels which supply water nozzles 76 adjacent the cutting teeth and in the bottom of the plough. The cable channel is at the rear of the plough; the cable enters at the top and is led out rearwardly at the bottom. In the hard bottom arrangement, the leading edge of the plough is inclined for better penetration and the vibrator is mounted directly on a stand on the bottom of the plough so as to increase its cutting power.